<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div id="s1">s1
    <div id="s2">s2</div>
</div>
<script>
    var s1=document.getElementById('s1')
    var s2=document.getElementById('s2')
    s1.addEventListener("click",function(e){
        console.log("s1 捕获事件");
        console.log(e.target)

    },true);
    s2.addEventListener("click",function(e){
        console.log("s2 捕获事件");
        if (s2.contains(e.target)){
            console.error('是我是我')
        }
    },false);
</script>
</body>
</html>
